Tessa Gray should be happy — aren’t all brides happy? Yet as she prepares for her wedding to Jem Carstairs, a net of shadows begins to tighten around the Shadowhunters of the London Institute. A new demon appears, one linked by blood and secrecy to the Magister, the man who plans to use his army of pitiless automatons, the Infernal Devices, to destroy the Shadowhunters. He needs only one last item to complete his plan of destruction.

He needs Tessa.

Tessa knows Axel Mortmain, the Magister, is coming for her, but not where or when he will strike. Charlotte Branwell, the head of the London Institute, is desperate to find Mortmain first. And the boys who lay equal claim to Tessa’s heart, Jem and Will, will do anything to save her. For though Tessa and Jem are now engaged, and Will knows he should force himself to find someone else to care for, he is as much in love with her as ever.

In the last words of a dying Shadowhunter reside the clue that might lead Tessa and her friends to Mortmain. But the Shadowhunters of the London Institute cannot stand alone, and in their homeland of Idris, the ruling body of the Clave doubt their claims that Mortmain is coming. Deserted by those who should be their allies and with their enemies closing in, the Shadowhunters find themselves trapped when Mortmain seizes the medicine which is all that is keeping Jem alive. With his best friend at death’s door it is up to Will to risk everything to save the woman they both love.

To buy Will time, the warlock Magnus Bane joins with Henry Branwell to create a device that could help them to defeat the Magister. As those who love Tessa work to save her, and the future of the Shadowhunters that resides with her, Tessa realizes that the only person who can save her is herself —for in the discovery of her own true nature, Tessa begins to learn that she is more powerful than she ever dreamed possible. But can a single girl, even one who can command the power of angels, face down an entire army?

Danger and betrayal, secrets and enchantment, and the tangled threads of love and loss intertwine as the Shadowhunters are pushed to the very brink of destruction in the breathtaking conclusion to the Infernal Devices trilogy.

ERMAGERD.

So... heartbreaking...

SPOILER ALERT - GO READ CLOCKWORK ANGEL AND CLOCKWORK PRINCE

Tessa and Will, Tessa and Jem...

So of course Jem gets even sweeter in this book, which makes it impossible to hate him even though you really really want to for stealing Tessa from Will, because Will is the best, right?